Topological insulator structure

a topological and insulator technology, applied in the direction of electrical equipment, galvano-magnetic hall-effect devices, semiconductor devices, etc., can solve the problems of ferromagnetic materials (including magnetic doped tis) having anomalous hall resistance larger than a kiloohm (k) and the inability to observe the qahe therein

Active Publication Date: 2014-06-26
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, any TI which can observe the QAHE therein has not been achieved.
Further, even a ferromagnetic material...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

embodiment 1

T=30 mK, 5 QL Sample, Back Gate Structure

[0070]The magnetically doped TI quantum well film is 5 QL Cr0.15(Bi0.10Sb0.9)1.85Te3 (i.e., the film has 5 QL), and the substrate 30 is STO substrate, in the embodiment 1. Different back gate voltages (Vb) are applied to the magnetically doped TI quantum well film, and the corresponded Hall curves are tested at the temperature of 30 mK.

[0071]Referring to FIGS. 6 to 9, H is the magnetization and μ0 is the vacuum permeability, in the μ0H. The unit of μ0H is Tesla (T). The RAH of the sample is changed with Vb, and the hysteresis phenomena can be seen, which means that the sample has a good ferromagnetic property. When 0V≦Vb≦10V, the change of RAH with Vb is not very great. When Vb=−4.5 V, RAH=25.8 kΩ.

embodiment 2

T=1.5K, 4 QL Sample, Back Gate Structure

[0072]The magnetically doped TI quantum well film is 4 QL Cr0.22(Bi0.22Sb0.78)1.78Te3, and the substrate 30 is STO substrate, in the embodiment 2.

[0073]Different back gate voltages (Vb) are applied to the magnetically doped TI quantum well film, and the corresponded Hall curves are tested at the temperature of 1.5K. Referring to FIG. 10, the hysteresis phenomena can be seen, and the hysteresis loops have a “square” shape, which means that the sample has a great ferromagnetic property. By changing Vb, a relatively large RAH can be achieved. The RAH increases first and then decreases with the increasing of the Vb. When Vb=45 V, RAH reaches the maximum value, which is 10 kΩ. This value is approximate to 0.4 quantum resistance, the quantum resistance is 25.8 kΩFIG. 11 shows that the Rxx-μ0H curves show a butterfly shaped hysteresis pattern, which also reveals that the sample has a great ferromagnetic property. In addition, when Vb=45V, the anomalo...

embodiment 3

T=100 mK, 4 QL Sample, Back Gate Structure

[0074]The magnetically doped TI quantum well film is 4 QL

[0075]Cr0.22(Bi0.22Sb0.78)1.78Te3, and the substrate 30 is STO substrate, in the embodiment 3.

[0076]Different back gate voltages (Vb) are applied to the magnetically doped TI quantum well film, and the corresponded Hall curves are tested at the temperature of 100 mK. FIG. 13 shows that the hysteresis phenomena can be seen, which means that the sample has a good ferromagnetic property. When 0V≦Vb≦20V, the change of RAH with Vb is not very great. RAH is about 0.6 quantum resistance. When Vb=10 V, RAH reaches the maximum value, (RAH)max=0.59 h·e−2, which is about 15.3 kΩ. This value exceeds a half of quantum resistance and is larger than the greatest known anomalous Hall resistance ever achieved in the world at this time. FIG. 14 shows that the change of the Rxx with the change of the Vb is more obviously than the change of the Ryx with the change of Vb as shown in FIG. 13. Especially, wh...

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Abstract

A topological insulator structure includes an insulating substrate and a magnetically doped TI quantum well film located on the insulating substrate. A material of the magnetically doped TI quantum well film is represented by a chemical formula of Cry(BixSb1-x)2-yTe3. 0<x<1, 0<y<2. Values of x and y satisfies that an amount of a hole type charge carriers introduced by a doping with Cr is substantially equal to an amount of an electron type charge carriers introduced by a doping with Bi. The magnetically doped TI quantum well film is in 3 QL to 5 QL.

Description

RELATED APPLICATIONS[0001]This application claims all benefits accruing under 35 U.S.C. §119 from China Patent Application No. 201210559564.X, filed on Dec. 21, 2012 in the China Intellectual Property Office, the disclosure of which is incorporated herein by reference. This application is related to commonly-assigned applications entitled, “METHOD FOR GENERATING QUANTIZED ANOMALOUS HALL EFFECT,” filed **** (Atty. Docket No. US50945); “ELECTRICAL DEVICE,” filed **** (Atty. Docket No. US50947); “METHOD FOR MAKING TOPOLOGICAL INSULATOR STRUCTURE,” filed **** (Atty. Docket No. US50948); and “TOPOLOGICAL INSULATOR STRUCTURE,” filed **** (Atty. Docket No. US50946).BACKGROUND[0002]1. Technical Field[0003]The present disclosure relates to a topological insulator structure.[0004]2. Discussion of Related Art[0005]If an electric current flows through an electrical conductor in a magnetic field perpendicular to the electric current, a measurable voltage difference between two sides of the elect...

Claims

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Application Information

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IPC IPC(8): H01L43/06
CPCH10N52/00H10N52/01H10N50/85
Inventor XUE, QI-KUNHE, KEMA, XU-CUNCHEN, XIWANG, LI-LICHANG, CUI-ZUFENG, XIAOLI, YAO-YIJIA, JIN-FENG
Owner TSINGHUA UNIV
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